HFM Asset Management & CADDS Energy Partnered to develop a Case Study on Part J of the NCC 2019

Along with our research partner CADDS Energy, we prepared one of many case studies. These studies helped explain the fundamental changes proposed to Part J of the National Construction Code (NCC) 2019 Volume One and supported the Public Comment Draft recently released.

Australian Building Codes Board has published our Case Study on their website, and it can be downloaded here.

The case studies used computer modelling to analyse current examples of buildings designed to comply with Part J of the NCC 2016, against the proposed provisions of Part J of the 2019 NCC Volume One.

The purpose of the studies was to uncover real evidence on the proposed changes and understand what a 2019 compliant building looks like.

Findings:

We compared our case study, which used JV3 to comply with Part J NCC 2016, against a 2019 compliant DTS reference model. The take-home messages from the comparison were:

Our case study was initially designed to be high performing and achieved compliance with the 2019 NCC without additional modifications/upgrades

There were clear benefits from the existing energy efficient design principles such as:

High-efficiency double glazing

Solar passive orientation and design (e.g. shorter elevations on the east and west)

Significant external shading

Solar PV system

There was a clear advantage in using performance solutions such as JV3 instead of prescriptive DTS requirements as it allowed:

Comparing the proposed Deemed to Satisfy (DTS) 2019 vs. the current DTS 2016 provisions of Part J we saw:

Stringency increases aimed at reducing energy and GHG emissions

Our modelling for a class 5 building showed a reduction of 32% in power and 37% in greenhouse gas emissions

Simplification of the Deemed to Satisfy (DTS) method:

Moving away from the glazing calculator to a wall/glazing façade thermal calculation

Consideration of the effects of thermal bridging on affecting overall R-Value.

Additional Comments:

The expansion in compliance options to NABERS Commitment Agreement and Greenstar as verification methods will provide greater flexibility, reduce modelling requirements and documentation.

HFM Asset Management supports the use of NABERS Commitment Agreement as a means of bridging the gap between design and operation.

In many cases, renewables (e.g. Solar PV) could be used under JV3 to mitigate/offset the increase in stringency provisions and achieve compliance

Concerns around envelope requirements and compliance for smaller buildings – e.g. small end of town may face high costs for added stringency.

HFM wishes to acknowledge CADDS Energy for their assistance and the other presenters involved such as WSP, Team Catalyst and Arup who also provided excellent case studies and contributed significantly to the overall discussions.